PML-N president Shahbaz Sharif has outrightly rejected the election results and hinted his party would launch protests against the alleged rigging of polls. "Some five other parties including PPP have raised the rigging issue in polls. After consulting them, I will announce the future course of action," he said.

Pakistani cricket hero-turned-politician Imran Khan’s Tehreek-i-Insaf is all set to emerge as the single largest party, trends showed on Wednesday, as the party of his jailed chief rival, ousted Prime Minister Nawaz Sharif, rejected the count as “blatantly” rigged.

With just 42 percent of the total vote counted till around 5am, the Election Commission of Pakistan had Khan's PTI leading in 113 of 272 contested National Assembly constituencies.

Sharif's Pakistan Muslim League-Nawaz (PML-N) was ahead in 66 constituencies, and the Pakistan Peoples Party (PPP), led by the son of assassinated two-time Prime Minister Benazir Bhutto, led in 39 constituencies.

An official at the Election Commission said early on Thursday that final results had been delayed by technical failures. As most of the political parties dismissed the results over alleged rigging, the delay gave further fuel to their charges.

Chief Election Commissioner of Pakistan Sardar Raza Khan called a press conference at four in the morning to dispel the allegations. He said that the delay was purely technical in nature.

"There's no conspiracy, nor any pressure in delay of the results. The delay is being caused because the result transmission system has collapsed," secretary Babar Yaqoob told reporters.

Imran Khan's camp was increasingly confident of winning the election, although it still appeared likely to fall short of the 137 seats needed for a majority in the National Assembly, raising the prospect it would need to find coalition partners among smaller parties and independents.

Khan's party spokesman, Fawad Chaudhry, tweeted "Congratulations to the nation on a new Pakistan! Prime Minister Imran Khan", although his party has officially held off on declaring victory.

Wednesday's voting was marred by a suicide bombing that killed 31 people near a polling station in Quetta, capital of the southwestern province of Baluchistan. Islamic State claimed responsibility.

OPPONENTS CRY FOUL

PML-N president Shahbaz Sharif has outrightly rejected the election results and hinted his party would launch protests against the alleged rigging of polls. "Some five other parties including PPP have raised the rigging issue in polls. After consulting them, I will announce the future course of action. Pakistan has suffered today," he told journalists at a press conference at midnight.

"We will fight this injustice and use all options." Sharif termed it the dirtiest election in Pakistan's history. "This is a horrible situation which I have never seen in my 30-year political career. These were the dirtiest polls in Pakistan's history," he said.

PML-N spokesperson Marriyum Aurangzeb raised objections over the counting process and alleged that her party's agents were forced out from several polling stations. "The counting process is being carried out behind closed doors and changes are being made to Form-45," she told reporters.

According to Election Commision of Pakistan website, the first Form 45 is the Result of the Count' showing the number of valid votes for each contesting candidate and ballot papers excluded from the count.

Supporters of Imran Khan celebrate near his residence in Bani Gala in Islamabad on Wednesday.

PPP's Maula Bux Chandio also claimed that his party's agents were not allowed inside polling stations in Badin while Pak Sarzameen Party leader Raza Haroon made the same claim about the treatment meted out to their agents at different polling stations across Karachi.

Thursday's election results will mark only the second civilian transfer of power in Pakistan's 71-year history.

Campaigning too was plagued for months by allegations that the powerful armed forces have been trying to tilt the race in Khan's favour after falling out with the outgoing ruling party of Sharif, who was jailed on corruption charges this month.

The PML-N had sought to cast the election as a referendum on democracy, and has said it was campaigning to protect the "sanctity of the vote", a reference to a history of political interference by the military.

About 371,000 soldiers have been stationed at polling stations across the country, nearly five times the number deployed at the last election in 2013.

The PML-N and the PPP both said their monitors in many voting centres had not received the official notifications of the precinct's results, but instead got hand-written tallies that they could not verify.

'WE WILL TAKE ACTION'

Election official Yaqoob promised that all formal complaints would be investigated. "If there are certain polling stations where they have any complaints, we should be approached. We will take action," Yaqoob said.

But he said he had no knowledge of widespread problems. "We're getting complaints that on some polling stations where certain parties are losing, their polling agents are leaving without taking the verified results," he said.

Khan has staunchly denied allegations by PML-N that he is getting help from the military, which has ruled Pakistan for about half of its history and still sets key security and foreign policy in the nuclear-armed nation. The army has also dismissed allegations of meddling in the election.

Pakistan's new government will face a mounting and urgent in-tray, from a brewing economic crisis to worsening relations with on-off ally the United States to deepening cross-country water shortages.

An anti-corruption crusader, Khan has promised an "Islamic welfare state" and cast his populist campaign as a battle to topple a predatory political elite hindering development in the impoverished mostly-Muslim nation of 208 million people, where the illiteracy rate hovers above 40 percent.

If Khan's lead holds, his party will likely be able to form a government with smaller parties and independents, avoiding the prospect of weeks of haggling.

Such a delay could further imperil Pakistan's economy, with a looming currency crisis expected to force the new government to turn to the IMF for Pakistan's second bailout since 2013. PTI has not ruled out seeking succour from China, Islamabad's closest ally.